Currently, in order for the quantum-dot electroluminescent device to emit white light, a method of stacking quantum-dot red, blue and green emitting layers is mainly adopted, i.e., the white light is obtained by mixing three primary colors. The white light obtained through this method, emitted by the quantum-dot electroluminescent device, has a chromaticity which tends to vary with an applied voltage. In addition, the preparation of a light-emitting layer with a multilayer structure leads to complexity of the process and high costs.